The invention relates generally to product packaging systems and, more particularly but not by way of limitation, to a bag former and former assembly for use in a packaging system.
As shown in FIG. 1, a product packaging system 100 comprising three major components: the product 105 to be packaged; packaging material 110 from which packages are formed; and former 115. Product 105 may comprise virtually any material including, for example, liquids, powders, solids and bulk material. Package material 110 is typically a thin film with text and graphics that identify the product (e.g., potato chips or coffee) and supplier (e.g., Company XYZ). Former 115 is an assembly that manipulates package material 110 into the desired shape (e.g., a rectangular or elliptical bag) and forms the package""s seal, while the packaging system itself provides the product and actually seals package material 110 to form an enclosed volume (packages 120).
FIG. 2 shows a typical prior art longitudinal-type packaging system 200. As shown, product 105 and packaging material 110 is introduced to former 115 where material 110 is shaped and aligned by wing 205 to conform about product filing tube 210 and to form a seam. The seam is longitudinally sealed by sealing device 215 so that material 110 forms a cylinder 220. Feeding device 225 pulls packaging material 110 (specifically cylinder 220) downward so that sealing/cutting device 230 seals cylinder 220 to form product package 120.
For economic reasons, it is important that packaging systems such as 100 and 200 operate at high speeds and for long periods of time. This, in turn, requires that former 115 be constructed of material that is mechanically strong (e.g., rigid), extremely wear resistant, not susceptible to corrosion and presents low resistance to packaging material 110. The latter is important because as packaging material 110 is pulled over wing 205 component wear can, over time, result in a former 115 that creates uneven seams or wrinkles, creases or tears packaging material 110 as it is pulled over the wing""s 205 surface.
Former 115 is typically designed to produce a package having a predetermined size and shape. For example, a first former may be designed to produce rectangular bags having a width of four (4) inches for use in small snack or candy products. A second former may be designed to produce elliptical bags having a width of eight (8) inches for use with breakfast cereal products. Still another former may be designed to produce bags having a width of twenty four (24) inches to package industrial/commercial frozen food. Accordingly, when a different size package (for the same or a different product) is needed, former 115 is replaced by a different former designed to produce a package having the new/correct size. For the reasons discussed above, typical former assemblies are fabricated out of solid stainless steel and, as a result, are quite heavy. Thus, it is often difficult for a worker to change the former because of the former""s weight. Large formers often require multiple personnel or a small crane to change. This, in turn, reduces the amount of time the packaging system can be used to package product. This is especially true for larger formers such as those used to package, for example, industrial food packages (e.g., commercial-size containers of frozen foods).
Thus, it would be beneficial to provide a former that is wear and corrosion resistant, presents low friction to packaging material and yet is significantly lighter than current formers.
In one embodiment the invention provides a former that includes a wing having a concave surface with periodic openings, a tube coupled to the wing along a first edge to form a crown and a base coupled to the tube along a second edge of the tube and conforming substantially to the shape of the tube and further adapted to couple to a packaging system. The tube may be designed to facilitate fabrication of substantially any shape package such as, for example, a rectangle, a square, a circle or an ellipse. In another embodiment of the invention, the tube includes periodic openings. In yet another embodiment of the invention, the former may include a cross-bar (coupled to the base and adapted to attach to a packaging system), a top-plate (coupled to the wing substantially parallel to the plane of the cross-bar and adapted to attach to a packaging system) and spacers that interconnect the cross-bar and top-plate. The wing may be fabricated from 2-WL rigidized stainless steel, the tube and base from stainless steel and the cross-bar, top-plate and spacers from anodized aluminum or other lightweight material. In addition, the cross-bar and top-plates may incorporate hollowed-out regions. Finally, a former in accordance with the invention may include a secondary product inlet to allow the introduction of additional material (other than the primary product) into a package formed by the former.
A former in accordance with the invention may be substantially less heavy than a prior art former designed to fabricate the same package while simultaneously providing improved operating performance, vis a vis the ability to generate packages with uniform seams, and equal or improved durability.